1. Field of the Invention
This invention relates to an information processing system, with a communication function, which does not affect the operation of an application even if communication is disconnected due to a failure.
2. Description of Related Art
For an information processing system such as a notebook personal computer, electronic pocket-notebook, or hand-held terminal, which has a communication program or a communication unit installed in it, it has become more popular for a user to send data over a wireless communication line as mobile telephones have become more popular. In this case, the user starts an application in the information processing system starts a communication program, and then connects a communication line to the information processing system, using a mobile telephone via a communication unit, for communication with another information processing system.
In a situation in which the quality of wireless communication is poor, for example, when data is sent from a mobile telephone while the user is in a vehicle or when the communication quality changes dynamically due to interference or external noises, the communication line sometimes becomes disconnected. If such a failure occurs before all the data is sent, the user must start the application and the communication program again in order to connect the communication line to the information processing system. This applies also to wire communication, such as a LAN, in which communication quality is relatively reliable and therefore an application does not anticipate that communication will be disconnected before all the data has been sent. When a connection is disconnected in such a case, the application is terminated prematurely and does not send data. This means that the user must repeat the same operation again from the beginning. In particular, a user who has been using a database or electronic mail must type the user ID and password again. This operation is very troublesome.
One known method for recovering from a communication line disconnection is described in "Using Network PDA" in Nikkei Communication No. 222.
In this method, an application program is modified so that data to be sent is stored in a spool area within a sending system before communication starts. The communication program also sends data from the spool area to a receiving system. The communication program in the receiving system also stores received data in its spool area. The application program in the receiving system references the spool area to obtain data. When communication is disconnected, for example, due to a failure, the communication program automatically reconnects the communication line to the information processing system, eliminating the need for the user to repeat the operation.